Vacuum powered pump



April 1966 w. BUNKER 3,244,357

VACUUM POWERED PUMP Filed April 27, 1964 2 Sheets-Sheet l INVENTOR.

Mam Bank! 3 I 5 7/ BY 2 4 H15 ATTORNEY April 1966 w. BUNKER 3,244,357

VACUUM POWERED PUMP /0 INVENTOR.

Mam Buzz/(er '9" 3f 7 BY Law United States Patent 3,244,357 VACUUM PUWERED PUMP Ward Bunker, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Apr. 27, 1964, Ser. No. 362,749 11 Claims. ((31. 23052) This invention relates to vacuum powered pumps and more particularly to an improved valving arrangement for alternately communicating the power chambers of such a pump with different sources of pressure.

One problem in many vacuum operated pumps is that the selector valve arrangement therein for effecting a pressure'differential across the power unit thereof often includes a large number of operative parts that are expensive to manufacture; difiicult to service; susceptible to 'wear; and a cause of reduced pump efliciency because of a substantial power consumption. Furthermore, selector valving elements presently found in vacuum operated pumps may fail to operate in a desired timed relationship with the pumping action wherein the efficiency of the pump is undesirably reduced.

Accordingly, an object of the present invention is to improve vacuum powered pumps or the like by the provision therein of an integral selector valve arrangement prove the operative efliciency and responsiveness of a selector valve for association with a vacuum powered pump by the provision of a reciprocable and rotatable valving element controlled by a reciprocable actuator member and spring biased, cam guiding means for effecting a desired alternate communication of two sources of pressure with the power chambers of the pump.

A still further object of the present invention is to provide such an improved selector valve assembly including -a valving chamber having a coaxially aligned guide member, valving element and actuator element therein with mutually cooperating camsurfaces thereon for effecting linearly guided and rotative movement of the valving element to produce a desired alternate communication of two pressure sources with the power chambers in the pump and wherein the operative parts of the selector valve assembly are quickly disassembled from the valving chamber as a unit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a schematic view showing the pump of the present invention in association with an auxiliary air system of an automotive vehicle;

FIGURE 2 is a view in vertical section taken along the longitudinal axis of the improved pump;

FIGURE 3 is a view in vertical section taken along the line 3-3 of FIGURE 2;

FIGURE 4 is a view in horizontal section taken along I the line 44 of FIGURE 3;

FIGURE 5 is a view in top elevation of a valving element of the present invention;

FIGURE 6 is a view in top elevation of a guide member of the present invention;

FIGURE 7 is a view in top elevation of a valve element actuator member; and

FIGURE 8 is a fragmentary view, partially in elevation and partially in section, showing the valving assembly in an intermediate operative position.

Referring now to the drawings, in FIGURE 1 an auxiliary air supply system is illustrated including a vacuum operated compressor 10 constructed in accordance with certain principles of the present invention having a vacuum line 12 connected thereto and a pair of manifolded discharge lines 14, 15 supplying a reservoir 16 having an outlet line 18 therefrom for supplying compressed air to an air horn, an auxiliary air lift suspension system or the like.

In FIGURE 2., the improved vacuum operated pump .10 more particularly is illustrated as including a first housing portion 20 and a second housing portion 22, each having peripheral flange portions 24 joined at suitable circumferentially spaced locations by suitable fastening means, for example, screws 26. Within the housing portions 20, 22 is a flexible diaphragm element 28 that extends completely across the pump housing where the outer peripheral edge is held between the housing flange portions 24 in sealing engagement therewith. The diaphragm 28 serves in conjunction with housing portions 20, 22 to form a power chamber 30' and a power chamber 32 on either side of the diaphragm 28, respectively. Directed axially through the power chambers 30, 32 is a piston rod 34 including a first portion 36 within the chamber 39 having a threaded end thereof directed through the diaphragm 28 centrally thereof into threaded engagement with one end of va second portion 3 of the rod 34 located within the chamber 32. The diaphragm 28 is thereby held in sealing engagement between the two-piston rod portions 36, 38 and in operative engagement with rod 34 whereupon it is reciprocated when a pressure differential occurs across diaphragm 28.

The piston rod portion 36 is arranged coaxially with a pump cylinder 40 formed as an integral projection from the housing portion 20 and the piston rod portion 38 similarly is coaxially aligned with a like pump cylinder 42 formed as an integral projection from the housing portion 22. Within the pump cylinder 42 is slidably mounted V a piston 44 secured to the piston rod portion 38. The

piston 44 includes an annular seal element 46 and an inlet valve assembly representatively shown as including a ball check element 48 biased by a suitably retained spring 50 into valve sealing engagement with a seat formed in a passageway 52 communicating with power chamber 32 and the interior of cylinder 42. A discharge valve assembly-for the pump cylinder 42 is representatively illusto the piston rod portion 36 to be slidably mounted within the pump cylinder 40in sealing engagement with the interior walls thereof. A discharge valve is supported on the pump cylinder 44) for preventing fluid flow back into an expanding pumping volume in cylinder 40.

In the vacuum pump illustrated in FIGURE 2, a pumping arrangement is illustrated wherein, upon selectively, alternately directing a source of vacuum and atmospheric pressure to either of the power chambers 30, 32, a differential force is produced across the diaphragm 28 for reciprocating the piston rod 34 and piston elements 44, 64

thereon so as to produce a double-acting, single-stage compression of atmospheric air.

In accordance with certain of the principles of the present invention the pumping structure is made more efiicient and more economical to manufacture by the inclusion therein of improved means to effect the alternate communication of power chambers 30, 32 with atmosphere and a source of vacuum. More particularly, an improved selector valve assembly 66 is included in an enlarged shoulder portion 68 formed integrally with the housing portion 22. The shoulder 68 has a large diameter opening '70 therein closed at the upper end thereof by a threaded cap element 72 having an opening 74 therethrough communicating the opening 70 with atmosphere. Below the large diameter opening 70 in shoulder portion 68 is formed a smaller diameter Opening 76 communicating with a passageway 78 perpendicular thereto and formed in an exteriorly threaded side extension 80 of the housing shoulder portion 68 serving as an inlet fitting for connection to the vacuum line 12 whereby the small diameter opening 76 is in communication with a source of vacuum, for example, the inlet manifold of the automobile.

Within the shoulder 68 opposite to extension 80 therein is formed a passageway 82 having one end thereof opening into the large diameter opening 70 and being inclined downwardly, as best illustrated in FIGURE 3, to intersect an axially directed passageway 84 in body portion 22 that is in communication with the power chamber 32. Likewise, housing portion 22 includes an axial passageway 86 therein located above passageway 84 and to one side thereof, as best illustrated in FIGURES 2 and 3, for communication with an opening 88 through diaphragm 28 adjacent the outer periphery thereof and an opening 90 in housing portion 20 aligned with the opening 88 whereby chamber 30 is communicated with opening 70.

Referring now more particularly to the valving assembly 66, it can be seen with reference to FIGURE 2 that the assembly is comprised of a relatively small number of working parts more specifically including a spring element 92, a valving element 94, a guide member 96 and a valve actuator assembly 98, all arranged coaxially with one another within the large and small diameter openings 70, 76. The valving element 94, more specifically, is generally cylindrically shaped and is supported in slidingly sealing engagement with the inner wall formed by opening 70 to thereby serve to divide the opening into an atmospheric pressure region 97 and a vacuum pressure region 99.

The valve actuator assembly 98 is operated upon reciprocation of the piston rod 34 by axially spaced, generally conically-shaped cam surfaces 100, 102 on the piston rod portion 38 which slidably engage a plunger element 104 of assembly 98 directed through the body 22 into the opening 76 coaxially therewith. Camming engagement between the shoulders 100, 102 and the element 104 causes it to be moved linearly against the biasing action of a return spring 106 surrounding the plunger 104 and having one end thereof biased against the underside of the guide element 96 and the opposite end thereof engaging a disc element 108 snapped into a groove on the plunger 104. Fluid leakage from the opening 76 into the pump chamber 32 along the plunger 104 is prevented by an annular sealing element 110 in body 22 surrounding the plunger 104 in sealing engagement therewith.

The upper end of the plunger 104 of actuator 98 has crossed and mutually perpendicularly arranged actuating members 112, each having a somewhat semicircular cross section and each being linearly guided by a groove 114 in the guide member 96 where each of the grooves 114 intersects a central opening 116 in the guide member. Concentrically located within opening 116 is a guide ring 117 through which the upper end of the plunger 104 moves upon actuation thereof by the camming surfaces on piston rod 54 and spider arms 118 on member 96 serve to support ring 117. The relationship between grooves 114 and actuating members 112 is maintained by a set screw 119 for preventing relative rotation of the guide member 96 with respect to the body portion 22.

The guide member 96 further includes diametrically opposed pairs of upwardly curving guide surfaces 120, 121 between each of the guide openings 114 with each such surface having a leading shoulder 122 and a trailing shoulder 124, as best illustrated in FIGURE 6, with the leading and trailing shoulders 122, 124 of adjacent curved surfaces serving to define the guide grooves 114.

When the valving element 94 is in the controlling position illustrated in FIGURE 2 the curved upper surfaces 120, 121 supportingly receive like curved surfaces 126, 127, respectively, formed on depending projections 128 on the underside of the valving element 94 with the projections 128 also including a shoulder 130 thereon that is biased against one of the leading edges 122 on the guide member 96 by engagement of the spring element 92 on the upper surface of the valving element 94. By virtue of the interlocking or indexing relationship between guide member shoulders 122 and valve projection shoulders 130, a first pair of diametrically opposed recesses 132, 133 formed in the outer periphery of valving element 94 between the upper end thereof and a point above the lower end thereof are arranged so that recess 132 is in overlying relationship with the intersection between passageway 86 and the large diameter opening 70 whereby the pumping chamber 30 is communicated with atmosphere through passageway 74, the atmospheric pressure region 97, the recess 132, passageways 86, 88 and 90. Likewise, a pair of diametrically opposed recesses 134, in the outer periphery of the generally cylindrical valving element 94 at a point therein located ninety degrees from the recesses 132, 133 and formed from the bottom of the valving element to a point spaced from the top thereof are arranged so that the recess 135 overlies the end of the passageway 82 whereby the pumping chamber 32 is communicated with a source of vacuum through passageway 78, small diameter opening 76, opening 116 in the guide member 96 and thence into the low-pressure region 99 of the valving as- ;embly 66 through the recess 135 and passageways 82,

Upon so communicating chambers 30, 32 with atmosphere and vacuum, respectively, the pressure differential across diaphragm 28 reciprocates the piston rod 34 to cause the piston 44 to compress fluid in the pumping cylinder 42 from whence it is discharged through the discharge valve into the high-pressure reservoir 16. During reciprocation of rod 34 in this direction, the camming surface 100 forces the plunger 104 vertically, as illustrated in FIGURE 8, whereby the upper semicircularly curved actuating elements 112 engage the curved surfaces 126, 127 on the valving element projections 128 to raise the valving element 94 linearly upwardly in the large diameter opening 70 of the valving assembly 66. During linear movement of the valving element, shoulders 130 on the valving element and guide shoulders 122 on the guide member 96 are held in sliding engagement by the spring 92 to prevent rotative movement of the valve 66 into another of its controlling positions. However, at a point slightly before the end of the piston stroke, the cam surface 100 raises the plunger 104 sufliciently to cause the shoulder 130 to clear the guide shoulder 122 at which time the curved surface 126 slides downwardly on the semicircularly curved head of member 112 and is forced downwardly by the spring 92 clockwise along the adjacent curved guide surface 121, as illustrated in FIG- URE 8. The valve element 94 is thereby rotated until the shoulder 130 on the trailing projection 128 engages the side of the raised actuating member portions 112 at the base of surface 120 in FIGURE 8. The valve is thereby stopped following substantially a ninety degree rotation preferably before completion of the upward movement of the plunger 104 whereby the valve will be in its second controlling position immediately upon completion of the above-discussed compression stroke. Linear movement during actuation to different control positions also serves to prevent the valve from binding within open- 's 7- I When in its second controlling position, the recess 135 is located to overlie the opening 86 whereby the chamber is communicated with the source of vacuum through the fluid passageways discussed above and at the same time the recess 133 is rotated to overlie the passageway 82 whereby the chamber 32 is communicated with atmosphere through the fluid passageways described above. Accordingly, the pressure differentials across the diaphragm 28 are thus alternately reversed and the piston rod 34 is thereby reciprocated in opposite directions to cause pistons 44, 64 to compress fluid in cylinders 40, 42 and discharge it through conduits 14, 15 into the reservoir 16. When the pistons move toward their respective power chambers 30, 32, a vacuum is produced in the expanding pump chambers formed by cylinders 40, 42 so as to cause ball 58 to seat and ball 48 to open whereby fluid is drawninto cylinders 40, 42 from chambers 36 32. While the valving assembly is illustrated in association witha double-acting, single-stage vacuum powered pump, it is equally well suited for association with a vacuum powered pump of the double-acting, two-stage type as illustrated in the copending application of Frank E. La-

Flame', Serial No. 120,642, filed June 29, 1961, now Patent No. 3,151,804, or any other operative device requiring the controlled valving of two sources of fluid to two or more points of use. Since the valving element re quires only a small amount of power to be actuated, it is specially suited for use in vacuum powered pumps. It

is, however, also suited for use in other pump environments, as for example, a pressure powered pump that is either diaphragm or piston actuated.

One feature of the above-described arrangement is that the component partsof the valve assembly 66 can be removed for repair or cleaning merely by unscrewing the cap 72 and set screw 119 and extracting the coaxially arranged spring element 92, valving element 94, guide element 96 and valve actuator assembly 98 from the concentrically arranged openings 70, 76 in the body 22 as a single unit.

In light of the above remarks, it will be appreciated that the present invention reduces the cost of manufacturing vacuum powered pumps and the like and also simplifies maintenance and increases efliciency and the reliability of operation of such pumps.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A vacuum pump assembly comprising, a housing, diaphragm means in said'housing cooperating therewith for forming first and second power chambers, said housing including first and second compression cylinders on either side of said diaphragm means, a piston rod directed through said power chambers and having opposite ends thereof coaxial with said first and second compression cylinders, piston means on either end of said piston rod slidably supported within said first and second cylinder means, said piston rod secured to said diaphragm means for reciprocation thereby, a valve chamber in said housing, first and second passageway means in said housing communicating said first and second power chambers with said valve chamber, valve means rotatably supported within said valve chamber, said valve means including an outer peripheral surface slidably sealingly engaging said housing for dividing said valve chamber into two pressure regions, means forming first and second passageways in said valve means for alternately communicating said first and second housing passageways with the two pressure regions, and actuator means for unidirectionally rotating said valve means within said valve cham- 6 ber during opposite reciprocation of said pistonrod by said diaphragm means to effect such alternate communication.

2. In the combination of claim 1, said actuator means including means for reciprocating said valve means within said valve chamber to prevent rotative binding there of with respect to said housing.

3. In a vacuum pump the combination of a housing, diaphragm means in said housing forming therewith first and second power chambers, said housing means including a valve chamber communicating with atmosphere and a source of vacuum, means forming first and second passageways in said housing for communicating said first and second power chambers respectively with said valve chamber, a rotatable valve element in said valve chamber including portions thereon cooperating with said housing means for separating said valve chamber into an atmospheric side and a vacuum side, means forming a recess in said rotatable valve element for alternately communicating said first and second housing passageways with atmosphere and vacuum, a piston rod secured to said diaphragm means for reciprocation thereby, and valve actuator means including a reciprocable plunger selectively engaged by said piston rod upon opposite reciprocation thereof, said valve actuator means including means responsive to movement of said plunger for unidirectionally rotating said valve element during opposite reciprocation of said piston rod whereby said valve element alternately communicates said first and second power chambers with atmosphere and a source of vacuum for effecting the reciprocation of said piston rod.

4. In the combination of claim 3, said actuator means including means for selectively reciprocating said valve element upon reciprocation of the piston rod.

5. In a valve assembly for a differential pressure piston driven pump having a reciprocable piston rod the combination of, a valve housing forming a chamber communicable with a first and a second source of pressure, a rotatable valve element supported within said valve housing chamber and cooperating therewith to divide said chamber into a high-pressure and a low-pressure region, passageway means in said rotatable valve element communicable with the high and low-pressure regions, a guide member Within said valve chamber having a guide surface thereon, a valve actuator element having a portion thereof engageable with said valve element, said actuator element portion being linearly guided by a first part of the guide surface in said guide element, a depending projection on said rotatable valve element guidably engaged by a second part of said guide surface in said guide member, said valve actuator element serving to move said valve member linearly out of guided engagement with said guide element, said valve element projection and actuator element portion coacting upon movement of said valve element out of guided engagement with said guide member to rotate said valve element.

6. In a valve assembly for a differential pressure driven pump having a reciprocable piston rod, the combination of, housing means forming a valve chamber, a guide member in said chamber, valve means in said chamber for dividing said chamber into two pressure regions, first coacting surfaces on said valve means and guide member for indexing said valve means in a first predetermined position, valve actuator means, second coacting surfaces on said valve member and said actuator means inclined toward said first coacting surfaces, spring means for biasing said first coacting surfaces together, said valve actuator means including means for moving said second coacting surfaces a predetermined distance for disengaging said first coacting surfaces to effect a predetermined movement of said valve means in said chamber.

7. In the combination of claim 6, said valve actuator means including an elongated rod and a valve member lifting portion, said rod adapted to be moved linearly upon reciprocation of the pump piston rod for effecting movement of said valve means out of engagement with said guide member.

8. In the combination of claim 6, said valve member, guide member and spring means being arranged colinearly for quick removal from said valve chamber.

9. In a valve assembly for a diiferential pressure piston driven pump having a reciprocable piston rod, the combination of, housing means forming a valve chamber, passageway means in said housing means, a generally cylindrical rotatable valve member supported within said valve chamber having an outer peripheral portion slidably sealingly engaging said housing means to divide said chamber into a high and a low-pressure region, said valve element including recess means communicating with the high and low-pressure regions of said valving chamber, said recess means including a first pair of diametrically opposed recesses extending along a first part of the outer periphery of said valve member in communication with one of the pressure regions and a second pair of diametrically arranged recesses formed along a second part of the outer periphery of said valving member in communication with another of the pressure regions, and means adapted to be responsive to reciprocation of the piston rod for selectively unidirectionally rotating said valve member to alternately locate the first and second pairs of valve recesses in communication with said valve housing passageways.

10. In a vacuum pump having a diaphragm actuated piston rod, the combination of, a valve housing, a rotatable valve element within said housing having first cam means thereon, a guide member in said housing having second cam means thereon for linearly guiding said valve element relative to said guide member, valve actuator means for linearly moving said valve element with respect to said guide member for moving said first and second cam means out of linearly guided engagement, said first cam means and said actuator means including coopcrating inclined surfaces thereon for rotatably guiding said valve element following movement thereof out of linearly guided relationship with said guide member, means for biasing said valve element relative to said actu ator means for effecting guided relative rotation therebetween, said second cam means on said guide members limiting rotation of said valving element following a predetermined advancement thereof with respect to said valve housing.

11. in a valving mechanism for association with a vacuum powered pump having a diaphragm actuated piston rod the combination of, housing means forming a valve chamber, a generally cylindrical valve element supported within said valve chamber and cooperating with said housing means for separating said valve cylinder into high and low-pressure regions, spring means in said valving chamber on one side of said valve element for biasing it in a first direction, a guide member in said valve chamber on the opposite side of said valve element having a camming surface thereon, a depending projection on said valve element, said camming surface on said guide element cooperating with said depending valve projection for linearly guiding said valve element, valve actuator means including a portion engageable With said depending valve projection for moving said valve element linearly out of guided relationship with said guide member, said spring producing relative cam guided rotation between said valve element and said actuator means upon movement of said element out of linearly guided relationship with said member.

References Cited by the Examiner UNITED STATES PATENTS 7/1907 Eggleston 230-170 3/1953 Osburn 23052 X ROBERT M. WALKER, Primary Examiner. 

1. A VACUUM PUMP ASSEMBLY COMPRISING, A HOUSING, DIAPHRAGM MEANS IN SAID HOUSING COOPERATING THEREWITH FOR FORMING FIRST AND SECOND POWER CHAMBERS, SAID HOUSING INCLUDING FIRST AND SECOND COMPRESSION CYLINDERS ON EITHER SIDE OF SAID DIAPHRAGM MEANS, A PISTON ROD DIRECTED THROUGH SAID POWER CHAMBERS AND HAVING OPPOSITE ENDS THEREOF COAXIAL WITH SAID FIRST AND SECOND COMPRESSION CYLINDERS, PISTON MEANS ON EITHER END OF SAID PISTON ROD SLIDABLY SUPPORTED WITHIN SAID FIRST AND SECOND CYLINDER MEANS, SAID PISTON ROD SECURED TO SAID DIAPHRAGM MEANS FOR RECIPROCATION THEREBY, A VALVE CHAMBER IN SAID HOUSING, FIRST AND SECOND PASSAGEWAY MEANS IN SAID HOUSING COMMUNICATING SAID FIRST AND SECOND POWER CHAMBERS WITH SAID VALVE CHAMBER, VALVE MEANS ROTATABLY SUPPORTED WITHIN SAID VALVE CHAMBER, SAID VALVE MEANS INCLUDING AN OUTER PERIPHERAL SURFACE SLIDABLY SEALINGLY ENGAGING SAID HOUSING FOR DIVIDING SAID VALVE CHAMBER INTO TWO PRESSURE REGIONS, MEANS FORMING FIRST AND SECOND PASSAGEWAYS IN SAID VALVE MEANS FOR ALTERNATELY COMMUNICATING SAID FIRST AND SECOND HOUSING PASSAGEWAYS WITH THE TWO PRESSURE REGIONS, AND ACTUATOR MEANS FOR UNIDIRECTIONALLY ROTATING SAID VALVE MEANS WITHIN SAID VALVE CHAMBER DURING OPPOSITE RECIPROCATION OF SAID PISTON ROD BY SAID DIAPHRAGM MEANS TO EFFECT SUCH ALTERNATE COMMUNICATION. 